BACKGROUND: Recombinant human TSH (rhTSH) has become the modality of choice for radioiodine remnant ablation (RRA) in low-risk thyroid cancer patients. AIMS AND METHODS: The aims of the present prospective randomized study were to evaluate the impact of TSH stimulation procedure (hypothyroidism vs. rhTSH) on quality of life (QoL) of thyroid cancer patients undergoing RRA and to evaluate efficacy of both procedures. L-T4 was initiated in both groups after thyroidectomy. After randomization, L-T4 was discontinued in hypothyroid (hypo) group and continued in rhTSH group. A measure of 3.7 GBq of radioiodine was given to both groups. The functional assessment of chronic illness therapy-fatigue (FACIT-F) was administered from the early postoperative period to 9 months. Socio-demographic parameters, anxiety and depression scales were also evaluated (CES-D, BDI and Spielberger state-trait questionnaires). At 9 months, patients underwent an rhTSH stimulation test, diagnostic (131)I whole body scan (dxWBS) and neck ultrasonography. RESULTS: A total of 74 patients were enrolled for the study. There was a significant decrease in QoL from baseline (t0) to t1 (RRA period) in the hypothyroid group with significant differences in FACIT-F TOI (P < 10(-3)), FACT-G total score (P = 0.005) and FACIT-F total score (P = 0.003). By contrast, QoL was preserved in the rhTSH group. In the multivariate analysis, FACIT-TOI changes were only affected by the modality of TSH stimulation performed for RRA. From 3 to 9 months, changes of QoL scales and subscales were no longer statistically different in both groups of patients. Based on serum rhTSH-stimulated Tg alone (Tg < 0.8 microg/l, BRAHMS Tg Kryptor), no difference in ablation success was observed between rhTSH and hypothyroidism groups, 91.7% and 97.1%, respectively. A higher rate of persistent thyroid remnants was observed in the rhTSH arm, although in most cases uptake was < 0.1% and of no clinical significance. CONCLUSIONS: rhTSH preserves QoL of patients undergoing RRA with similar rates of ablation success compared to hypothyrodism. However, there is a wide heterogeneity in the clinical impact of hypothyroidism.